.TH std::ranges::zip_view::size 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::ranges::zip_view::size \- std::ranges::zip_view::size

.SH Synopsis
   constexpr auto size()                                   \fB(1)\fP (since C++23)
       requires (ranges::sized_range<Views> && ...);
   constexpr auto size() const                             \fB(2)\fP (since C++23)
       requires (ranges::sized_range<const Views> && ...);

   Returns the number of elements in the zip_view. Provided only if each underlying
   (adapted) range satisfies sized_range.

   Equivalent to:

 return std::apply
 (
     [](auto... sizes)
     {
         using CT = /*make-unsigned-like-t*/<std::common_type_t<decltype(sizes)...>>;
         return ranges::min({CT(sizes)...});
     },
     /*tuple-transform*/(ranges::size, views_)
 );

.SH Parameters

   \fI(none)\fP

.SH Return value

   The number of elements, which is the minimum size among all sizes of adapted views.

.SH Example


// Run this code

 #include <algorithm>
 #include <cassert>
 #include <deque>
 #include <forward_list>
 #include <ranges>
 #include <vector>

 int main()
 {
     auto x = std::vector{1, 2, 3, 4, 5};
     auto y = std::deque{'a', 'b', 'c'};
     auto z = std::forward_list{1., 2.};

     auto v1 = std::views::zip(x, y);
     assert(v1.size() == std::min(x.size(), y.size()));
     assert(v1.size() == 3);

     [[maybe_unused]] auto v2 = std::views::zip(x, z);
 //  auto sz = v2.size(); // Error, v2 does not have size():
     static_assert(not std::ranges::sized_range<decltype(z)>);
 }

.SH See also

   ranges::size  returns an integer equal to the size of a range
   (C++20)       (customization point object)
   ranges::ssize returns a signed integer equal to the size of a range
   (C++20)       (customization point object)
